The long-term objective of this proposal is to gain a detailed understanding of the genetic control of eye-tissue determination in Drosophila. The specification of the eye primordium involves interactions between multiple signaling pathways (dpp, wg, hh) and transcription factors (Toy, Ey, Eya, So, Dae, Hth, Tsh) linked in a regulatory cascade that controls initiation of neurogenesis in the eye. In this grant, we propose to investigate the function of these molecules in initiating neurogenesis, to analyze the role of a novel gene in this process, and to identify other factors that contribute to eye specification. The specific aims of this grant are: 1. to elucidate the molecular mechanisms leading to initiation of neurogenesis by dissecting the transcriptional control of the proneural gene atonal; 2. to investigate at molecular and genetic levels the function of l(3)96Bb-CG5807, a locus required for eye specification; 3. to identify novel regulators of eye specification relying on a modified misexpression screen. Since the factors studied in this proposal are conserved and play significant roles in vertebrate eye development, our work will provide insights into genetic factors that are central to mammalian eye development and are linked to congenital disorders of the eye and brain.